Method For Controlling The Operation Of  A Washing Machine, And System For Controlling Freezes For A Washing Machine

ABSTRACT

The present invention relates to a method for controlling the operation of a washing machine, which ensures the operation stability of the washing machine through proper control such as sensing freezes or preventing freezes even in an environment such as in a wintertime environment in which the temperature is low causing the washing machine to freeze, and which achieves an improvement in a management aspect such as a countermeasure taken upon the occurrence of freezing and a countermeasure taken for preventing freezing, wherein the counter measures are taken based on the accurate information on whether or not the washing machine is frozen.

TECHNICAL FIELD

The present invention relates to a method for controlling the operation of a washing machine and a system for controlling freezes for a washing machine.

BACKGROUND ART

In general, washing machines include an outer tub to contain wash water and an inner tub to contain clothing (hereafter, referred to as ‘fabrics’), rotatable in the outer tub, and wash the fabrics as the inner tub rotates.

The washing machines can be classified into a top loading type with an inner tub that is vertically mounted such that fabrics can be loaded from the tops of the machines, and rotates about the vertical axis and a front loading type with an inner tub that is horizontally mounted such that fabrics can be loaded through the fronts of the machines, and rotates about the horizontal axis.

The top loading type of washing machines can be largely classified into an agitator type and a pulsator type, then, the agitator type washes by rotating a wash bar standing at the center of an inner tub and the pulsator type washes by rotating a circular plate shaped-pulsator formed on the bottom of an inner tub or the inner tub.

The front loading type of washing machine, generally called a drum washing machine, includes a lifter on the inner side of a drum, which is an inner tub, and washes by lifting and dropping fabrics with the lifter as the drum is rotated.

There are various types of washing machines, as described above, but any one of them is equipped with a water supply system that supplies wash water to the outer tub and/or the inner tub and drain system that exhausts wash water from the outer tub after washing, rinsing, and spinning.

The washing machines of the related art has a problem in that the water supply system or the drain system cannot normally operate due to freeze of wash water under the environment such as wintertime where the external air drops in temperature to zero or less.

DISCLOSURE Technical Problem

The present invention has been made in an effort to solve the aforementioned problems and it is an object of the present invention to provide a method of a washing machine which can prevent a washing machine from freezing.

Further, it is another object of the present invention to provide a method of controlling a washing machine which suspends the operation of a washing machine, depending on freeze conditions that are set in consideration of the internal temperature of the washing machine.

Further, it is another object of the present invention to provide a method of controlling a washing machine which can preclude a washing machine from freezing, by allowing a user to immediately recognize the temperature drop, when the internal temperature of the washing machine dropped to a predetermined level or less.

Further, it is another object of the present invention to provide a method of controlling a washing machine that can accurately sense whether a washing machine freezes, by determining several times whether the washing machine freezes at each of operational steps of the washing machine.

Further, it is another object of the present invention to provide a method of controlling a washing machine that can sense whether a washing machine freezes.

Further, it is another object of the present invention to provide a method of controlling a washing machine which can prevent wash water from freezing by removing the water remaining inside the washing machine.

Further, it is another object of the present invention to provide a method of controlling a washing machine which can improve convenience in the use by allowing a user to selectively remove the water remaining inside the washing machine.

Further, it is another object of the present invention to provide a system for managing freeze of a washing machine that can sense and prevent freeze at a short distance or a long distance by using a communication system.

Technical Solution

A method of controlling a washing machine of the present invention includes: a step (a) that senses the internal temperature of a washing machine through a temperature sensor; and a step (b) that operates a heater in the washing machine, when the temperature sensed in step (a) is lower than a set-temperature.

Alternatively, a method of controlling a washing machine including at least one of a water supply pump, a drain valve, and a drain pump of the present invention, includes: a step (a) that senses temperature by means of a temperature sensor disposed in the water supply valve, the drain valve, or the drain pump in the washing machine; and a step (b) that operates the water supply valve, the drain valve, or the drain pump which is equipped with the temperature sensor.

Alternatively, a method of controlling a washing machine of the present invention includes: a step (a) that performs draining, when the water level in an outer tub is a set-water level or more, before supplying wash water; a step (b) that compares the internal temperature of the washing machine with a reference temperature, draining takes a reference time or more in step (a); and a step (c) that outputs a first error message, when the internal temperature of the washing machine is lower than the reference temperature in step (b).

Alternatively, a method of controlling a washing machine of the present invention includes: a step (a) that performs draining, when the water level in an outer tub is higher than a first set-water level that is set to determine whether an overflow has occurred, before supplying wash water into the outer tub; a step (b) that performs draining, when the water level in the outer tub is higher than a second set-water level set to be lower than the first set-water level, after step (a); a step (c) that compares the internal temperature of the washing machine with a predetermined reference temperature, when the time taken to discharge the water to a predetermined level in step (b) is larger than a predetermined drain-set time; and a step (d) that outputs a first error message, when the internal temperature of the washing machine is lower than the predetermined reference temperature in step (c).

Alternatively, a method of controlling a washing machine of the present invention includes a step (a) that supplies water into an outer tub; a step (b) that compares the internal temperature of the washing machine with a third reference temperature, when the water level in the outer tub is lower than a first water supply-set water level, after wash water is supplied for a first water supply-set time; and a step (c) that outputs a first error message, when the internal temperature of the washing machine is lower than the third reference temperature in step (b).

Alternatively, a method of controlling the operation of a washing machine of the present invention includes: a step (a) that senses temperature before water is supplied into an outer tub; a step (b) that supplies water into the outer tub; a step (c) that senses the water level in the outer tub; and a step (d) that outputs a fifth error message, when the water level in the outer tub does not reach a first set-water level within a first set-time. Alternatively, a method of controlling a washing machine of the present invention includes: a step (a) that senses the amount of change in output voltage of a water supply valve, when power is applied to the water supply valve; and a step (b) that performs unfreezing, when it is sensed that the output voltage of the water supply valve has reduced by a predetermined value or more in step (a).

Alternatively, a method of controlling a washing machine of the present invention includes: a step (a) that senses the amount of change in output voltage of a drain pump, when power is applied to the drain pump; and a step (b) that performs unfreezing, when it is sensed that the output voltage of the drain pump has reduced by a predetermined value or more in step (a).

Alternatively, a method of controlling a washing machine of the present invention includes: a step (a) that senses the amount of change in output voltage of a drain valve, when power is applied to the drain valve; and a step (b) that performs unfreezing, when it is sensed that the output voltage of the drain valve has reduced by a predetermined value or more in step (a).

A system for controlling freezes for a washing machine of the present invention includes: a washing machine that determines whether wash water freezes, and transmits a signal about whether the wash water freezes to the outside through a communication medium; and a remote controller that receives whether the wash water freezes from the washing machine.

Alternatively, a system for controlling freezes for a washing machine of the present invention includes: a remote controller that allows a user to input a signal about anti-freezing of wash water and transmits the anti-freezing signal to a washing machine through a communication medium; and a washing machine that receives the anti-freezing signal from the remote controller and performs anti-freezing for the wash water.

Advantageous Effects

The method of controlling a washing machine of the present invention has the effect of being able to prevent a washing machine from freezing even under an environment at a low temperature such as a hard winter season.

Further, the method of controlling a washing machine of the present invention can effectively perform anti-freezing or unfreezing for the parts of a washing machine, which may freeze, by directly heating the parts.

Further, the method of controlling a washing machine of the present invention has the effect of being able to prevent freezing by using self-heating that is generated when the parts operate, without a specific heater for heating the parts that frequently come in contact with wash water.

Further, the method of controlling a washing machine of the present invention has the effect of being able to accurately sense whether to freeze.

Further, the method of controlling a washing machine of the present invention has the effect of being able to accurately sense whether a washing machine freezes, by determining several times whether the washing machine freezes at each of operational steps of the washing machine.

Further, the method of controlling a washing machine of the present invention has the effect of being able to determine whether to freeze, before a predetermined operation such as washing, rinsing, and spinning.

Further, the method of controlling a washing machine of the present invention has the effect of being able to ensure safety by stopping the operation of a washing machine when the washing machine freezes, and to induce taking appropriate measures by outputting an error that says that freezing has occurred to the outside.

Further, the method of controlling a washing machine of the present invention has the effect of being able to prevent water from remaining and freezing in the washing machine.

Further, the method of controlling a washing machine of the present invention has the effect of being able to prevent the washing machine from being left frozen for a long time, by performing unfreezing when it is sensed that the washing machine has frozen.

Further, the method of controlling a washing machine of the present invention has the effect of being able to simply and accurately sense whether to freeze, by sensing whether to freeze through a change in output voltage or output current of electric components of the washing machine, such as a water supply valve, a drain valve, or a drain pump.

Further, a system for controlling freezes for a washing machine of the present invention has the effect of being able to provide information about freezing of the washing machine to a user at a long distance.

Further, a system for controlling freezes for a washing machine of the present invention can check whether the washing machine has frozen at a long distance through a communication network.

Further, a system for controlling freezes for a washing machine of the present invention can allow an operation for preventing the washing machine from freezing at a long distance through a communication network.

DESCRIPTION OF DRAWINGS

FIG. 1 is a side cross-sectional view of a washing machine according to an embodiment of the present invention.

FIG. 2 is a partial enlarged view showing the bottom of the outer tub shown in FIG. 1.

FIG. 3 is a block diagram illustrating the configuration of controlling a washing machine according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating an example of the configuration of supplying power to prevent freeze in a washing machine according to an embodiment of the present invention.

FIG. 5 is a flowchart illustrating a method of controlling a washing machine according to a first embodiment of the present invention.

FIG. 6 is a flowchart illustrating a method of controlling a washing machine according to a second embodiment of the present invention.

FIG. 7 is a flowchart illustrating a method of controlling a washing machine according to a third embodiment of the present invention.

FIG. 8 is a flowchart illustrating a method of controlling a washing machine according to a fourth embodiment of the present invention.

FIGS. 9 a to 9 c are flowcharts illustrating a method of controlling a washing machine according to a fifth embodiment of the present invention.

FIG. 10 is a diagram illustrating another example of the configuration of supplying power to prevent freeze in a washing machine 100 according to an embodiment of the present invention.

FIG. 11 is a flowchart illustrating a method of controlling a washing machine according to a sixth embodiment of the present invention.

FIG. 12 is a flowchart illustrating a method of controlling a washing machine according to a seventh embodiment of the present invention.

FIG. 13 is a flowchart illustrating a method of controlling a washing machine according to an eighth embodiment of the present invention.

FIG. 14 is a flowchart illustrating a method of controlling a washing machine according to a ninth embodiment of the present invention.

FIG. 15 is a flowchart illustrating a method of controlling a washing machine according to a tenth embodiment of the present invention.

FIG. 16 is a flowchart illustrating a method of controlling a washing machine according to an eleventh embodiment of the present invention.

FIG. 17 is a flowchart illustrating a method of controlling a washing machine according to a twelfth embodiment of the present invention.

FIG. 18 is a flowchart illustrating a method of controlling a washing machine according to a thirteenth embodiment of the present invention.

FIG. 19 is a flowchart illustrating a method of controlling a washing machine according to a fourteenth embodiment of the present invention.

FIG. 20 is a flowchart illustrating a method of controlling a washing machine according to a fifteenth embodiment of the present invention.

FIG. 21 is a flowchart illustrating a method of controlling a washing machine according to a sixteenth embodiment of the present invention.

FIG. 22 is a flowchart illustrating a method of controlling a washing machine according to a seventeenth embodiment of the present invention.

FIG. 23 is a graph showing an output voltage change (a) when a water supply valve is unfrozen and an output voltage change (b) when a drain valve is unfrozen.

FIG. 24 is a flowchart illustrating a method of controlling a washing machine according to an eighteenth embodiment of the present invention.

FIG. 25 is a block diagram illustrating the flow of control in a system for controlling freezes for a washing machine according to an embodiment of the present invention.

FIG. 26 is a flowchart illustrating a first embodiment of a system for controlling freezes for a washing machine.

FIG. 27 is a flowchart illustrating a second embodiment of a system for controlling freezes for a washing machine.

FIG. 28 is a flowchart illustrating a third embodiment of a system for controlling freezes for a washing machine.

BEST MODE

The advantages and features of the present invention, and methods of achieving them will be clear by referring to the exemplary embodiments that will be describe hereafter in detail with reference to the accompanying drawings. However, the present invention is not limited to the exemplary embodiments described hereafter and may be implemented in various ways, and the exemplary embodiments are provided to complete the description of the present invention and let those skilled in the art completely know the scope of the present invention and the present invention is defined by claims. Like reference numerals indicate like components throughout the specification.

FIG. 1 is a side cross-sectional view of a washing machine 100 according to an embodiment of the present invention. FIG. 2 is a partial enlarged view showing the bottom of the outer tub shown in FIG. 1. FIG. 3 is a block diagram illustrating the configuration of controlling the washing machine 100 according to an embodiment of the present invention.

Referring to FIGS. 1 to 3, the washing machine 100 according to an embodiment of the present invention includes a cabinet 1 that forms the outer appearance, an outer tub 2 that is disposed inside the cabinet 1 and contains wash water, an inner tub 3 that is rotatably disposed inside the outer tub 2 and contains wash water, and a pulsator 4 that is rotatably disposed on the bottom inside the inner tub 3. A plurality of holes 3 h is formed through the inner tub 3 such that wash water can flow between the outer tub 2 and the inner tub 3. The outer tub 2 may be equipped with, at the top, a top cover with substantially the center portion open such that laundry can be loaded into the inner tub 3. Operation keys allowing a user to input various commands for controlling the operation of the washing machine and a control panel 11 providing a user interface by being equipped with a display that displays the operational status of the washing machine may be disposed on a side of the cabinet 1.

Further, the washing machine 100 according to an embodiment of the present invention a water supply channel 5 connected with an external water source such as a faucet and supplying wash water to the inner tub 2 and the outer tub, a water supply valve 6 opening/closing the water supply channel 5, a detergent box 7 containing a detergent, a drain channel 9 for discharging the wash water in the outer tub 2, a drain valve 8 opening/closing the drain channel 9, a drain pump 10 disposed in the drain channel 9, and a driving unit 13 selectively rotating the inner tub 3 or the pulsator 4.

The driving unit 13 may include a motor (not shown) that generates a rotational force and a clutch (not shown) that selectively transmit the rotational force of the motor to the inner tub 3 or the pulsator 4.

Further, the washing machine 100 according to an embodiment of the present invention may further include a control unit 4 that controls the overall operation of the washing machine, an anti-freezing selection unit 16 through which control commands for performing anti-freezing are inputted, a water level sensor 20 that senses the level of the wash water in the outer tub 2, a display unit 22 that displays the operational status of the washing machine, and a heater 28.

The heater 28 may be disposed on the bottom of the outer tub 2, and as shown in FIG. 2, on the bottom of the outer tub 2, a heater seat that forms a predetermined space for receiving the heater 28 is recessed and a heater cover 71 that covers the top of the heater seat may be disposed.

A hole 71 h may be formed through the heater cover 71 such that the wash water in the outer tub 2 can be discharged and a drain hole 74 may be formed through the heater seat such that wash water can be discharged to the drain channel 25.

The temperature sensor 18 may be disposed on the bottom of the outer tub 2. The temperature sensor 18 measures the temperature of wash water or the temperature of air in accordance with the level of the wash water in the outer tub 2. That is, it is apparent that the temperature sensed by the temperature sensor 18 is the temperature of the medium that is in contact with the temperature sensor 18, such that the temperature will be the temperature of wash water, when the temperature sensor 18 is submerged by wash water at a predetermined level or more in the outer tub 2, and it will be the temperature of air in other cases.

FIG. 4 is a diagram illustrating an example of the configuration of supplying power to prevent freeze in the washing machine 100 according to an embodiment of the present invention.

Referring to FIG. 4, the washing machine 100 according to an embodiment of the present invention may include a first power supply unit 24 and a second power supply unit 26.

The first power supply unit 24 supplies power with a predetermined magnitude or less with the washing machine in a standby status, not washing, rinsing, or spinning, and the display unit 22 can be operated even with the washing machine in the standby status by the power supplied from the first power supply unit 24.

The second power supply unit 26, which can supply power with a predetermined magnitude or more, supplies power for operating the heater 28. Further, the second power supply unit 26 can supply power to the driving unit 13, for washing, rinsing, or spinning.

In the washing machine 100 according to an embodiment of the present invention, the temperature sensor 18 senses temperature and the heater 28 operates, when the sensed temperature is lower than set-temperature, in order to prevent various parts of the washing machine from freezing with the washing machine in the standby status, not washing, rinsing, or spinning.

The set-temperature is reference temperature where the parts of the washing machine freeze, if they are left under a condition that is lower than the set-temperature, and preferably, it may be set at a subzero temperature.

Meanwhile, the power to be supplied to the temperature sensor 18 and the heater 28 can be supplied from any one of the first power supply unit 24 or the second power supply unit 26, but it is preferable that the first power supply unit 24 supplies power to the temperature sensor 18, when the washing machine is in the standby status without washing, rinsing, or spinning, and the first power supply unit 26 supplies power to operate the heater 28, when the temperature sensed by the temperature sensor 18 is lower than the set-temperature. There is an effect that it is possible to reduce the amount of power consumed by the temperature sensor 18 with the washing machine in the standby status.

When anti-freezing starts, the control unit 14 may control the first power supply unit 24 to supply power in order to operate the temperature sensor 18 and may control the second power supply unit 26 to supply power in order to operate the heater 28, when the temperature sensed by the temperature sensor 18 is lower than the set-temperature.

The start of anti-freezing means that a predetermined algorithm is executed to prevent the parts of the washing machine from freezing, and may be implemented in the following two ways.

First, anti-freezing automatically starts, when the washing machine is in the standby status without washing, rinsing, or spinning. It offers the advantage that it is not necessary to take a specific measure for preventing freeze of the washing machine.

Second, as shown in FIG. 3, as the anti-freezing selection unit 16 that allows selection of anti-freezing is provided in the washing machine, anti-freezing starts, only when there is a selection through the anti-freezing selection unit 16 by a user.

It should be noted that the starts (S501, S601, S701, and S801) of anti-freezing shown in FIGS. 5 to 8 can be implemented in any one of the two ways.

Further, the temperature sensor 18 will suffice as long as it can measure the internal temperature of the washing machine and may be a temperature sensor that is disposed inside the outer tub 2, a temperature sensor that is disposed in the water supply valve 6, a temperature sensor that is disposed in the drain valve 8, or a temperature sensor that is disposed in the drain pump 10, in order to measure the temperature of the wash water.

Meanwhile, the driving unit 13 may include a driving driver that controls the rotation of the motor by applying a driving signal to the motor. An IPM (Intelligent Power Module) may be exemplified as the driving driver and may be implemented by a driving circuit of a power device such as a power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor), or a power module provided with a self-protection function.

The IPM may be equipped with a temperature sensor in itself and the temperature sensor of the IPM may be used in the temperature sensing steps (S502, S602, S702, and S802) in FIGS. 5 to 8, which is described below.

On the other hand, though not shown in the drawings of the application, it should be construed that a washing machine for both washing and drying which has a function of drying too is included in the category of the washing machine of the present invention, and common washing machines for both washing and drying are equipped with a dry duct for supplying high-temperature air into the inner tub 3 with laundry loaded in order to dry the laundry and a temperature sensor that measures the internal temperature of the dry duct, so it should be noted that the temperature sensor 18 may be the temperature sensor that measures the internal temperature of the dry duct.

Further, the heater 28 may be disposed in the various parts of the washing machine 100. For example, freezing is likely to occur in the water supply valve 6, the drain valve 8, and the drain pump 10 through which wash water flows, such that the water supply pump 6, the drain valve 6, and/or the drain pump 10 may be equipped with the heater 28.

FIG. 5 is a flowchart illustrating a method of controlling a washing machine according to a first embodiment of the present invention.

As anti-freezing starts (S501), the temperature sensor 18 senses temperature (S502), and the heater 28 operates (S503 and S504), when the temperature sensed by the temperature sensor 18 is lower than a set-temperature. As long as freezing does not occur even after the heater 28 operates (S505), the temperature sensor 18 repeats measuring temperature (S506), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the heater 28 suspends the operation (S507 and S508). Thereafter, in accordance with whether freeze-sensing stops (S505), the temperature sensor 18 senses temperature (S506), and when the sensed temperature is lower than the set-temperature, the heater 28 operates again (S507 and S504).

The repeat of operating (S504) and suspending (S508) of the heater 28, based on the temperature sensed by the temperature sensor 18, as described above, keeps until the anti-freezing stops. Stopping the anti-freezing may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 6 is a flowchart illustrating a method of controlling a washing machine according to a second embodiment of the present invention.

As anti-freezing starts (S601), the temperature sensor 18 senses temperature (S602), and the heater 28 operates when the temperature sensed by the temperature sensor 18 is lower than a set-temperature (S603 and S604). As long as freezing does not occur even after the heater 28 operates, the temperature 18 repeats measuring temperature (S605), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the heater 28 suspends the operation (S606 and S608).

Further, the heater 28 suspends the operation when a set-time has passed (S606, S607, and S608), even though the temperature sensed by the temperature sensor 18 is not larger than the set-temperature in the present invention. The set-time may be set within a range where the heater 28 is not overheated, in consideration of the degree of heating of the heater 28.

Thereafter, in accordance with whether freeze-sensing stops (S609), the temperature sensor 18 periodically senses temperature (S602), and when the sensed temperature is lower than the set-temperature (S603), the heater 28 operates again (S604). The repeat of operating (S604) and suspending (S608) of the heater 28, based on the temperature sensed by the temperature sensor 18, as described above, keeps until the anti-freezing stops. Stopping the anti-freezing may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 7 is a flowchart illustrating a method of controlling a washing machine according to a third embodiment of the present invention.

As anti-freezing starts (S701), the temperature sensor 18 senses temperature (S702), and the heater 28 repeats operating and suspending (S704), when the temperature sensed by the temperature sensor 18 is lower than a set-temperature (S703). As long as freezing does not occur even after the heater 28 operates, the temperature 18 repeats measuring temperature (S705 and S706), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the heater 28 stops the operation (S707 and S708).

The reason that the section where the heater 28 does not operate is referred to as ‘suspending’ in step S704 and as ‘stopping’ in step S708 is because there is a difference in the way of operation of the heater 28 in steps S704 and S708. That is, the heater 28 repeats operating and suspending for a predetermined time in step S704, while the heater 28 that has stopped the operation in step S708 returns to step S705 from step S708, performs steps S706 and S707, and stands by without operating until it is operated again.

Meanwhile, in step S707, when the temperature sensed by the temperature sensor is lower than the set-temperature, the process returns to step S704 and the heater 28 repeats operating and suspending.

The third embodiment is different from the first embodiment described above in that when the temperature sensed by the temperature sensor 18 (S702) is lower, the heater 28 does not continuously operate but repeats operating and suspending (S704).

Stopping the anti-freezing in step S705 may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 8 is a flowchart illustrating a method of controlling a washing machine according to a fourth embodiment of the present invention.

As anti-freezing starts (S801), the temperature sensor 18 senses temperature (S802), and the heater 28 repeats operating and suspending (S803 and S804), when the temperature sensed by the temperature sensor 18 is lower than a set-temperature. As long as freezing does not occur even after the heater 28 operates, the temperature sensor 18 repeats measuring temperature (S805), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the heater 28 stops the operation (S808).

Further, the heater 28 stops the operation when a set-time has passed (S806, S807, and S808), even though the temperature sensed by the temperature sensor 18 is not larger than the set-temperature in the present invention. The set-time may be set within a range where the heater 28 is not overheated, in consideration of the degree of heating of the heater 28.

Thereafter, in accordance with whether freeze-sensing stops (S809), the temperature sensor 18 periodically senses temperature (S802), and when the sensed temperature is lower than the set-temperature, the heater 28 operates again (S803 and S804).

The reason that the section where the heater 28 does not operate is referred to as ‘suspending’ in step S804 and as ‘stopping’ in step S808 is because there is a difference in the way of operation of the heater 28 in steps S804 and S808. That is, the heater 28 repeats operating and suspending for a predetermined time in step S804, while the heater 28 that has stopped the operation in step S808 returns to step S802 from step S809 and stands by without operating until it is operated again in step S804.

Stopping the anti-freezing in step S809 may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIGS. 9 a to 9 c are flowcharts illustrating a method of controlling a washing machine according to a fifth embodiment of the present invention.

The washing machine 100 according to an embodiment of the present invention can perform a process of sensing whether the washing machine has frozen after operating for washing, rinsing, or spinning.

The washing machine 100 according to an embodiment of the present invention can accurately determine whether the washing machine freezes by primarily determining whether to freeze, which determines whether there is an overflow on the basis of comparison between a first set-water level with the water level in the outer tub 2 after power is supplied to the washing machine, and then performs draining on the basis of the result of the determination, through the series of flow shown in FIG. 9 a, by secondarily determining whether to freeze which performs draining when the water level in the outer tub 2 is a second set-water level or more by comparing the water level in the outer tub 2 with the second set-water level, through the series of flow shown in FIG. 9 b, and by thirdly determining whether to freeze through the series of flow shown in FIG. 9 c after supplying wash water into the outer tub 2 to perform the operations such as washing, rinsing, and spinning.

The process of primarily determining whether to freeze is described hereafter in detail with reference to FIG. 9 a.

As power is supplied and the washing machine starts operating (S901), the water level in the outer tub 2 is sensed by the water level sensor 20 and whether an overflow has occurred in the outer tub 2 is determined by comparing the sensed value with the first set-water level (S902). The reason that the process is performed in for sensing whether wash water has overflowed the outer tub 2, rising in the outer tub 2, by exceeding a predetermined level by a specific situation before the washing machine operates. For example, it may be the case when wash water keeps supplied into the outer tub 2 even with the power of the washing machine off due to a problem with the water supply valve 6. Therefore, it is preferable to set the first set-water level in consideration of the water level where the wash water overflows the outer tub 2.

When it is determined that the water level in the outer tub 2 is higher than the first set-water level in step S902, the control unit 14 controls the display unit 2 to output a third error message (S903). The third error message is a message that allows the user to recognize that an overflow has occurred.

Thereafter, the control unit 14 operates the drain pump 10 such that the wash water in the outer tub 2 is discharged (S904), and it turns off the third error message (S906), when the water level in the outer tub 2 drops down under a second set-water level within a predetermined time (S905). It is preferable to set the second set-water level to a zero water level with wash water in the outer tub 2 completely discharged. It is assumed that the second set-water level is a zero water level in the following description.

Meanwhile, when the water level in the outer tub 2 does not reach the second set-water level in step S905, the drain pump 10 keeps operating, and a when the water level in the outer tub 2 does not reach the second set-water level until the drain set-time reaches a first drain set-time (S907), the control unit 14 compares the temperature sensed by the temperature sensor 18 with a first reference temperature (S908). When it is determined that the sensed temperature is lower than the first reference temperature, as the result of comparing, the control unit 14 controls the display unit 22 to display a first error message, and when it is determined that the sensed temperature is higher than the first reference temperature, it controls the display unit 22 to output a second or a third error message (S910).

The process of secondarily determining whether to freeze is described hereafter in detail with reference to FIG. 9 b.

The process of secondarily determining whether to freeze is performed under the condition that the water level in the outer tub 2 is lower than the first set-water level. That is, this is for determining whether to freeze in the following processes, when it is determined that the water level sensed by the water level sensor 20 is lower than the first set-water level in step S902 or when the water level in the outer tub 2 drops down under the second set-water level through steps S902, S903, S904, S905, and S906.

The process of secondarily determining whether to freeze includes comparing the temperature sensed by the temperature sensor 18 with a second reference temperature. When the sensed temperature is the second reference temperature or less in step S911, the control unit 14 controls the display unit 22 to output the first error message (S912).

The water level in the outer tub in step S911 may be the first set-water level or less (which is possible when the process enters step S911 right after step S902) or the second set-water level (for example, the case when the water level in the outer tub 2 becomes the zero water level after steps S903, S904, S905, and S906 are sequentially performed). When the water level in the outer tub 2 is higher than the second set-water level and lower than the first set-water level, the temperature sensor 18 would sense the temperature of the wash water in the outer tub 2. In contrast, when the water level in the outer tub 2 is lower than the second set-water level (for example, the zero water level), the temperature sensor 18 would sense the temperature of the air in the washing machine. It is preferable that the second reference value is set at a subzero value in consideration of the freezing point of the wash water, or may be set as a several degrees under zero or less, considering that the temperature of the air is sensed by the temperature sensor 18.

When it is determined in step S911 that the temperature sensed by the temperature sensor 18 is lower than the second reference temperature, the control unit 14 determines that the temperature inside the washing machine is low enough for freezing and immediately controls the display unit 22 to output the first error message (S912). In sensing whether to freeze through steps S911 and S912, whether to freeze is determined or estimated on the basis of the sensed value by the temperature sensor 18, regardless of the features of discharging the wash water, and is not necessarily limited to the order shown in FIG. 9 b and may be performed at any point of time in the operation of the washing machine.

In particular, it is preferable to set the second set-temperature at an appropriate value through an experiment in step S911 to make it possible to estimate that the parts of the parts of the washing machine such as the water supply valve 6 or the drain pump 10 will freeze, with sufficient accuracy, when the temperature sensed by the temperature sensor 18 is the second temperature sensor or less.

On the other hand, when it is determined that the temperature sensed by the temperature sensor 28 is higher than the second reference temperature in step S911, the control unit 14 compares the water level sensed by the water level sensor 20 with the third set-water level (S913).

The case when the sensed water level is higher than the third set-water level means that there is wash water at the third water level or higher and at the first set-water level or less, in which the control unit 14 operates the drain pump 10 to drain (S915), determines that drain is normally performed, and senses the laundry weight, when a change in water level in the outer tub 2 is a reference value or more by draining for a second drain set-time (S916), compares the temperature sensed by the temperature sensor 18 with the third reference temperature (S918) when the change in water level is the reference value or less even though the second drain set-time has passed in step S916 (S917), controls the display unit 22 to output the first error message when the sensed temperature is lower than the third reference temperature (S919), and controls the display unit 22 to output the second error message (S920) when the sensed temperature is higher than the third reference temperature. The process of thirdly determining whether to freeze is performed under the condition that the water level in the outer tub 2 is the third set-water level or less, and may be performed after a laundry weight sensing step (S914) shown in FIG. 9.

When the laundry weight in the inner tub 6 is sensed in step S914, the patterns of the operation such as washing, rinsing, and spinning, which are performed later in accordance with the sensed laundry weight, are determined.

Water supplying (S921) is a step of supplying wash water into the outer tub 2 and the amount of the supplied wash water is set in accordance with the laundry weight sensed in step S914.

Step S923 that compares the water level in the outer tub 2 with the first water supply set-level to determine whether water is normally supplied is performed, when the first water supply set-time has passed (S922) after water starts to be supplied in step S912, and the control unit 14 determines that water is normally supplied when the water level sensed by the water level sensor 20 is the first water supply set-level, and compares again the water level in the outer tub 2 with the second water supply set-level (S928), after the second water supply set-time passes (S924). The first water supply set-level means a water level that is expected to be reached, when water is normally supplied for the first water supply set-time and the second water supply set-level means a target water level of the water that is supplied in to the outer tub 2 in accordance with the laundry weight sensed in step S914.

On the other hand, when it is determined that the water level in the outer tub 2 does not reach the first water supply set-level, the control unit 14 compares the temperature sensed by the temperature sensor 18 with a fourth reference temperature, when the sensed temperature is lower than the fourth reference temperature as the result of comparing, it controls the display unit 22 to display the first error message, whereas when the sensed temperature is higher than the fourth reference temperature, it controls the display unit to output a fourth error message. The fourth error message is a message that informs the user that water fails to be normally supplied due to a breakdown of the water supply valve 6 or the like.

Further, even if the water level sensed by the water sensor 20 does not reach the second water supply set-level in step S928, the control unit 14 can control the display unit 22 to display the fourth error message (S929).

By contrast, when the water level sensed by the water level sensor 20 is higher than the second water supply set-level in step S928, it means that water is normally supplied, and then the control unit 14 performs the washing operation through first washing by means of a predetermined algorithm, heating of the wash water in the outer tub 2 (S911) by operating the heater 28, second washing (S932), and draining (S933). In the first washing 930 and the second washing 933, the inner tub 6 and/or the pulsator 4 rotate and draining (S933) is achieved by the drain pump 10.

When the water level in the outer tub 2 does not reach a drain completion level even after draining (933) is performed for a third drain set-time (S939), the control unit 14 controls the display unit 22 to display the second error message (S940). On the contrary, when it is determined that the water level in the outer tub 2 is the drain completion level or less in step S934, it means that draining has been normally performed, and then the washing machine is turned off (S938), after rinsing (S935), provisional spinning (S936), and main spinning (S937) are performed, thereby finishing the operation of the washing machine.

FIG. 10 is a diagram illustrating another example of the configuration of supplying power to prevent freeze in a washing machine according to an embodiment of the present invention.

Referring to FIG. 10, a washing machine according to the present embodiment includes a first power supply unit 24 and a second power supply unit 26.

The first power supply unit 24 supplies power with a predetermined magnitude or less with the washing machine in a standby status, not washing, rinsing, or spinning, and the display unit 22 can be operated even with the washing machine in the standby status by the power supplied from the first power supply unit 24.

The second power supply unit 26, which can supply power with a predetermined magnitude or more, supplies power for operating the water supply valve 6, the drain valve 8, and the drain pump 10. Further, power can be supplied to the driving unit 13 from the second power supply unit 26 in washing, rinsing, or spinning.

The washing machine according to the present embodiment is prevented from freezing through self-heat generated when various parts operate, by sensing temperature with the temperature sensor 18 and operating the parts of the washing machine, when the sensed temperature is lower than a set-temperature, in order to prevent the parts of the washing machine from freezing with the washing machine in a standby status without washing, rinsing, or spinning.

The set-temperature is reference temperature where the parts of the washing machine freeze, if they are left under a condition that is lower than the set-temperature, and preferably, it may be set at a subzero temperature.

Meanwhile, the power to be supplied to the temperature sensor 18 and the heater 28 can be supplied from any one of the first power supply unit 24 or the second power supply unit 26, but it is preferable that the first power supply unit 24 supplies power to the temperature sensor 18, when the washing machine in the standby status, not washing, rinsing, or spinning, and the second power supply unit 26 supplies power to operate the heater 28, the water supply valve 6, the drain valve 10, or the drain pump 10, when the temperature sensed by the temperature sensor 18 is lower than the set-temperature. There is an effect that it is possible to reduce the amount of power consumed by the temperature sensor 18 with the washing machine in the standby status.

When anti-freezing starts, the control unit 14 may control the first power supply unit 24 to supply power in order to operate the temperature sensor 18 and may control the second power supply unit 26 to supply power in order to operate water supply valve 6, the drain valve 8, or the drain pump 10, when the temperature sensed by the temperature sensor 18 is lower than the set-temperature.

The start of anti-freezing means that a predetermined algorithm is executed to prevent the parts of the washing machine from freezing, and may be implemented in the following two ways.

First, anti-freezing automatically starts, when the washing machine is in the standby status without washing, rinsing, or spinning. It offers the advantage that it is not necessary to take a specific measure for preventing freeze of the washing machine.

Second, as shown in FIG. 10, as the anti-freezing selection unit 16 that allows selection of anti-freezing of the washing machine is provided, anti-freezing starts, only when there is a selection through the anti-freezing selection unit 16 by a user.

It should be noted that the starts (S1101, S1201, S1301, S1401, S1501, S1601, S1701, and S1801) of anti-freezing shown in FIGS. 11 to 18 can be implemented in any one of the two ways.

Further, the temperature sensor 18 of the present invention may be provided in any one of the water supply valve 6, the drain valve 8, or the drain pump 10 and is described in more detail in the following embodiments.

Embodiments of a method of preventing the water supply valve 6 from freezing are described hereafter with reference to FIGS. 11 to 18. However, the anti-freezing method illustrated in FIGS. 11 to 18 can be applied in the same way to prevent the drain valve 8 from freezing, in which it should be noted that the temperature sensor 18 is disposed in the drain valve 10 and there is a difference only in that whether to operate the drain valve 10 is determined in accordance with a sensed value of the temperature sensor 18.

FIG. 11 is a flowchart illustrating a method of controlling a washing machine according to a sixth embodiment of the present invention. The temperature sensor 18 is disposed in the water supply valve 6 in the present embodiment.

As anti-freezing starts (S1101), the temperature sensor 18 senses temperature (S1102), and the water supply valve 6 operates when the temperature sensed by the temperature sensor 18 is lower than a set-temperature (S1103 and S1104). As long as freezing does not occur even after the water supply valve 6 operates, the temperature 18 repeats measuring temperature (S1106), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the water supply valve 6 suspends the operation (S1107 and S1108). Thereafter, in accordance with whether freeze-sensing stops (S1105), the temperature sensor 18 senses temperature (S1106), and when the sensed temperature is lower than the set-temperature, the water supply valve 6 operates again (S1103 and S1104).

The repeat of operating (S1104) and suspending (S1108) of the water supply valve 6, based on the temperature sensed by the temperature sensor 18, as described above, keeps until the anti-freezing stops. Stopping the anti-freezing may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 12 is a flowchart illustrating a method of controlling a washing machine according to a seventh embodiment of the present invention.

The temperature sensor 18 is disposed in the water supply valve 6 in the present embodiment.

As anti-freezing starts (S1201), the temperature sensor 18 senses temperature (S1202), and the water supply valve 6 operates when the temperature sensed by the temperature sensor 18 is lower than a set-temperature (S1203 and S1204). As long as freezing does not occur even after the water supply valve 6 operates, the temperature 18 repeats measuring temperature (S1205), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the water supply valve 6 suspends the operation (S1206 and S1208).

Further, the water supply valve 6 suspends the operation when a set-time has passed (S1206, S1207, and S1208), even though the temperature sensed by the temperature sensor 18 is not larger than the set-temperature in the present invention. The set-time may be set within a range where the water supply valve 6 is not overheated, in consideration of the degree of heating of the water supply valve 6.

Thereafter, in accordance with whether freeze-sensing stops (S1209), the temperature sensor 18 periodically senses temperature, and when the sensed temperature is lower than the set-temperature (S1203), the water supply valve 6 operates again (S1204).

The repeat of operating and suspending of the water supply valve 6, based on the temperature sensed by the temperature sensor 18, as described above, keeps until the anti-freezing stops. Stopping the anti-freezing may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 13 is a flowchart illustrating a method of controlling a washing machine according to an eighth embodiment of the present invention.

The temperature sensor 18 is disposed in the water supply valve 6 in the present embodiment.

As anti-freezing starts (S1301), the temperature sensor 18 senses temperature (S1302), and the water supply valve 6 repeats operating and suspending (S1304), when the temperature sensed by the temperature sensor 18 is lower than a set-temperature (S1303). As long as freezing does not occur even after the water supply valve 6 operates (S1305), the temperature 18 periodically senses temperature (S1306), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature (S1307), the water supply valve 6 stops the operation (S1308).

The reason that the section where the water supply valve 6 does not operate is referred to as ‘suspending’ in step S1304 and as ‘stopping’ in step S1308 is because there is a difference in the way of operation of the water supply valve 6 in steps S1304 and S1308. That is, the water supply valve 6 repeats operating and suspending for a predetermined time in step S1304, while it stands by without operating before it operates again, by returning to step S1305 from step S1308 and performing step S1306 and S1307.

Meanwhile, in step S1307, when the temperature sensed by the temperature sensor is lower than the set-temperature, the process returns to step S1304 and the water supply valve 6 repeats operating and suspending.

In the present invention, the water supply valve 6 is not continuously operated, but repeatedly operated and suspended, when the temperature sensed by the temperature sensor 18 (S1302) is lower than the set-temperature.

Stopping the anti-freezing in step S1305 may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 14 is a flowchart illustrating a method of controlling a washing machine according to a ninth embodiment of the present invention.

The temperature sensor 18 is disposed in the water supply valve 6 in the present embodiment.

As anti-freezing starts (S1401), the temperature sensor 18 senses temperature (S1402), and the water supply valve 6 repeats operating and suspending (S1404), when the temperature sensed by the temperature sensor 18 is lower than a set-temperature (S1403). As long as freezing does not occur even after the water supply valve 6 operates, the temperature 18 periodically senses temperature (S1405), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the water supply valve 6 stops the operation (S1406 and S1408).

Further, the water supply valve 6 stops the operation when a set-time has passed (S1406, S1407, S1406, S1407, and S1408), even though the temperature sensed by the temperature sensor 18 is not larger than the set-temperature in the present invention. The set-time may be set within a range where the water supply valve 6 is not overheated, in consideration of the degree of heating of the water supply valve 6.

Thereafter, in accordance with whether freeze-sensing stops (S1409), the temperature sensor 18 periodically senses temperature, and when the sensed temperature is lower than the set-temperature, the water supply valve 6 operates again (S1403 and S1404).

The reason that the section where the water supply valve 6 does not operate is referred to as ‘suspending’ in step S1404 and as ‘stopping’ in step S1408 is because there is a difference in the way of operation of the water supply valve 6 in steps S1404 and S1408. That is, the water supply valve 6 repeats operating and suspending for a predetermined time in step S1404, while the water supply valve 6 that has operated the operation in step S1408 stands by without operating before it operates again in step S1403, by returning to step S1402 from step S1409.

Stopping the anti-freezing in step S1409 may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 15 is a flowchart illustrating a method of controlling a washing machine according to a tenth embodiment of the present invention.

The temperature sensor 18 is disposed in the drain pump 10 in the present embodiment.

As anti-freezing starts (S1501), the temperature sensor 18 senses temperature (S1502), and the drain pump 10 operates when the temperature sensed by the temperature sensor 18 is lower than a set-temperature (S1503 and S1504). As long as freezing does not occur even after drain pump 10 operates, the temperature 18 repeats measuring temperature (S1506), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the drain pump 10 suspends the operation (S1508 and S1508). Thereafter, in accordance with whether freeze-sensing stops (S1505), the temperature sensor 18 senses temperature (S1506), and when the sensed temperature is lower than the set-temperature, the drain pump 10 operates again (S1507 and S1504).

The repeat of operating (S1504) and suspending (S1508) of the drain pump 10, based on the temperature sensed by the temperature sensor 18, as described above, keeps until the anti-freezing stops. Stopping the anti-freezing may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 16 is a flowchart illustrating a method of controlling a washing machine according to an eleventh embodiment of the present invention.

The temperature sensor 18 is disposed in the drain pump 10 in the present embodiment.

As anti-freezing starts (S1601), the temperature sensor 18 senses temperature (S1602), and the drain pump 10 operates when the temperature sensed by the temperature sensor 18 is lower than a set-temperature (S1603 and S1604). As long as freezing does not occur even after drain pump 10 operates, the temperature 18 repeats measuring temperature (S1606), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the drain pump 10 suspends the operation (S1606 and S1608).

Further, the drain pump 10 suspends the operation when a set-time has passed (S1606, S1607, and S1608), even though the temperature sensed by the temperature sensor 18 is not larger than the set-temperature in the present invention. The set-time may be set within a range where the drain pump 10 is not overheated, in consideration of the degree of heating of the drain pump 10.

Thereafter, in accordance with whether freeze-sensing stops (S1609), the temperature sensor 18 periodically senses temperature, and when the sensed temperature is lower than the set-temperature, the drain pump 10 operates again (S1603 and S1604).

The repeat of operating and suspending of the drain pump 10, based on the temperature sensed by the temperature sensor 18, as described above, keeps until the anti-freezing stops. Stopping the anti-freezing may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 17 is a flowchart illustrating a method of controlling a washing machine according to a twelfth embodiment of the present invention.

The temperature sensor 18 is disposed in the drain pump 10 in the present embodiment.

As anti-freezing starts (S1701), the temperature sensor 18 senses temperature (S1702), and the drain pump 10 repeats operating and suspending (S1703 and S1704), when the temperature sensed by the temperature sensor 18 is lower than a set-temperature. As long as freezing does not occur even after drain pump 10 operates, the temperature 18 periodically measures temperature (S1706), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the drain pump 10 stops the operation (S1707 and 1708). The reason that the section where the drain pump 10 does not operate is referred to as ‘suspending’ in step S1704 and as ‘stopping’ in step S1708 is because there is a difference in the way of operation of the drain pump 10 in steps S1704 and S1708. That is, the drain pump 10 repeats operating and suspending for a predetermined time in step S1704, while the drain pump 10 that has stopped the operation in step B28 returns to step S1705 from step S1709, performs steps S1706 and S1707, and stands by without operating until it is operated again.

Meanwhile, in step S1707, when the temperature sensed by the temperature sensor is lower than the set-temperature, the process returns to step S1704 and the drain pump 10 repeats operating and suspending.

In the present invention, the drain pump 10 is not continuously operated, but repeatedly operated and suspended, when the temperature (S1702) sensed by the temperature sensor 18 is lower than the set-temperature.

Stopping the anti-freezing in step S1705 may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

FIG. 18 is a flowchart illustrating a method of controlling a washing machine according to a thirteenth embodiment of the present invention.

As anti-freezing starts (S1801), the temperature sensor 18 senses temperature (S1802), and the drain pump 10 repeats operating and suspending (S1803 and S1804), when the temperature sensed by the temperature sensor 18 is lower than a set-temperature. As long as freezing does not occur even after drain pump 10 operates, the temperature 18 periodically measures temperature (S1805), and when the temperature sensed by the temperature sensor 18 is higher than the set-temperature, the drain pump 10 stops the operation (S1806 and S1807).

Further, the drain pump 10 stops the operation when a set-time has passed (S1806, S1807, and S1808), even though the temperature sensed by the temperature sensor 18 is not larger than the set-temperature in the present invention. The set-time may be set within a range where the drain pump 10 is not overheated, in consideration of the degree of heating of the drain pump 10.

Thereafter, in accordance with whether freeze-sensing stops (S1809), the temperature sensor 18 periodically senses temperature, and when the sensed temperature is lower than the set-temperature, the drain pump 10 operates again (S1803 and S1804).

The reason that the section where the drain pump 10 does not operate is referred to as ‘suspending’ in step S1804 and as ‘stopping’ in step S1808 is because there is a difference in the way of operation of the drain pump 10 in steps S1804 and S1808. That is, the drain pump 10 repeats operating and suspending for a predetermined time in step S1804, while the drain pump 10 that has operated the operation in step S1808 stands by without operating before it operates again in step S1804, by returning to step S1802 from step S1809.

Stopping the anti-freezing in step S1809 may be based on the condition that a stop command is inputted through the anti-freezing selection unit 16 or may be based on the condition that a user inputs a control command for washing, rinsing, or spinning.

The embodiments described above show that it is possible to prevent a washing machine from freezing, using the heat that is generated when the electric parts in the washing machine operate, particularly, that it is possible to prevent freezing by operating the water supply valve 6, the drain valve 8, or the drain pump 10, which can be frequently frozen by remaining water.

FIG. 19 is a flowchart illustrating a method of controlling a washing machine according to a fourteenth embodiment of the present invention.

Referring to FIG. 19, the method of controlling a washing machine according to the fourteenth embodiment of the present invention senses the water level in the outer tub 2 before supplying wash water (S1901). It is possible to sense a water level, using a water level sensor 20 in step S1901.

The control unit 14 compares the water level sensed in step S1901 with a set-water level (S1902), makes water be supplied when the sensed water level is lower than the set-water level, and then makes operations such as washing, rinsing, and spinning be performed (S1903). The control unit 14 can make water be supplied by controlling the water supply valve 6 in step S1903.

On the other hand, when the water level sensed in step S1902 is higher than the predetermined wash level, the control unit 14 makes wash water be discharged by operating the drain pump 10, and when the water level in the outer tub 2 keeps sensed by the water level sensor 20 and the water level in the outer tub 2 sufficiently reduces before a drain set-time passes (S1905), the control unit 14 makes the wash water be supplied into the outer tub 2 by opening the water supply valve 6 and the operations such as washing, rinsing, and spinning (S1903).

In contrast, when the water level in the outer tub 2 does not sufficiently reduce and the drain set-time passes in step S1905, the control unit 14 controls the temperature sensor 18 to sense temperature (S6) and compares the sensed temperature with a reference temperature (S1907), and when the sensed temperature is lower than the reference temperature, the control unit controls the display unit 22 to output a first error message (S1908), and when the sensed temperature is higher than the reference temperature, it controls the display unit 22 to output a second error message (S1909).

Meanwhile, when draining is not enough even after the drain set-time passes in step S904 (S905), it may be assumed as one of the case when draining is not normally performed due to freezing of the drain system including the drain channel 9, the drain pump 10, and/or the drain valve 8 (first error message outputted) or the case when the drain pump 10 breaks down (second error message outputted).

Steps S1906 and S1907 are provided to determine which one it is of the two cases, and when it is determined that the temperature sensed in step S1906 is lower than the reference temperature in step S1907, it can be considered as when the washing machine operates in an environmental condition with a low temperature such as the wintertime and the control unit 14 controls the display unit 22 to output the first error message such that the user can recognize freezing of the drain system. The reference temperature is a value which is set by an experiment and makes it possible to considerably accurately estimate freezing, when water remains in the washing machine. It is preferable to set the reference temperature as a subzero value.

In contrast, when it is determined that the temperature sensed in step S1906 is higher than the reference temperature in S1907, it can be considered as the case when there is a low possibility that the water remaining in the washing machine freezes, so that the control unit 14 assumes that the reason for insufficient draining is the factors such as a breakdown of the drain pump 10 and clogging of the drain channel 9 or the drain valve 8, and controls the display unit 22 to output the second error message such that the user can recognize the reasons.

On the other hand, the reason of performing step S1902 before water is supplied while the washing machine operates is for determining whether to freeze using wash water when the wash water remains in the outer tub 2 before water is supplied for washing or rinsing, which has the advantage of being able to preclude unnecessary water supply by not supplying wash water thereafter, when freezing is sensed.

It is preferable that the control unit 14 controls the washing machine to stop the operation while outputting a corresponding error message in step S1908 or S1909 and the later operations are performed by specific operations of the user or under a stop condition that is output of the error message.

FIG. 20 is a flowchart illustrating a method of controlling a washing machine according to fifteenth embodiment of the present invention.

Referring to FIG. 20, as the washing machine is supplied with power and starts operating, temperature is sensed by the temperature sensor 18 before water is supplied into the outer tub 2 (S2001).

The control unit 14 compares the temperature T sensed in step S2001 with a reference temperature T1 (S2002). The reference temperature (S2001) may be set as a subzero value.

When it is determined that the temperature T sensed in step S2001 is lower than the reference temperature T1, that is, when the temperature of air sensed by the temperature sensor 18 is a subzero temperature, it can be considered that the washing machine is operating in a condition with a possibility of freezing, and accordingly, whether the washing machine freezes is determined the following steps S2011 to S2018.

In contrast, when it is determined that the temperature T sensed in step S2001 is higher than the reference temperature T, whether the water supply valve 12 or the drain pump 10 normally operates is determined in the following steps S2021 to S2030 and this process is discriminated from steps S2011 to S2018 which determine whether to freeze.

First, when it is determined that the sensed value T of the temperature sensor 18 is lower than a reference temperature T1 in step S2002, laundry weight sensing (S2011) for sensing the amount of laundry loaded in the inner tub 3 is performed, a target water level is set in accordance with the laundry weight, and water is supply (S2012).

Thereafter, the water level in the outer tub 2 is sensed by the water level sensor 20 and the control unit 14 determines whether the sensed value W of the water level sensor 20 has reached a first set-water level W1 within a predetermined first set-time. The first set-time W1 may be set as a value lower than the target water level set in accordance with the laundry weight in step S2011.

The first set-time may be set to be shorter than the time that the water level in the outer tub 2 takes to reach the target water level set in step S2011, under the condition that the water supply valve 12 normally operates.

When the sensed water level W does not reach the first set-water level W1, the control unit 14 determines that water has not been normally supplied and stops the operation of the washing machine, including stopping water supply (S2017), and controls the display unit 22 to display a fifth error message (S2018). The fifth error message is for saying that the washing machine is not being able to operate due to freezing.

Meanwhile, washing S2014 is performed, when it is determined that the sensed water level W has reached the first set-water level W1 within the first set-time in step S2013. The washing S2014 is a process of removing pollutants on the cloth by rotating the pulsator 4 or the inner tub 3, in which the rotational pattern of the pulsator 4 or the inner tub 3 can be set in various ways.

Draining S2015, a process of discharging the wash water in the outer tub 2 to the outside after the washing (S2014) is completed, is performed by the drain pump 10. The control unit 14 operates the drain pump 10 in the draining S2015.

The water level in the outer tub 2 is sensed by the water level sensor 20 in the draining S2015 and the control unit 24 determines whether the water level in the outer tub 2 has decreased to a second set-water level W2 or less after the draining S2015 (S2016).

When it is determined that the sensed value W of the water level sensor 20 is higher than the second set-water level W2 in step S2016, it means that draining has not been normally performed by the drain pump 10, and it can be considered that there is large possibility the reason is freezing of the drain pump 10, so that the control unit 14 stops the operation of the washing machine, including stopping draining (S2017), and controls the display unit 22 to display the fifth error message (S2018).

When it is determined that the sensed value W of the water level sensor 20 is lower than the second set-water level W2 in step S2016, rinsing S2003 that rinses out cloth by supplying again water into the outer tub 2 and spinning S2004 that spins cloth dry by rotating the inner tub 3 at a high speed can be sequentially performed.

On the other hand, when it is determined that the sensed value T of the temperature sensor 18 is higher than the reference temperature T1, steps S2021 to S2030 can be performed. Steps S2021 to S2026 can be substantially considered as the same processes as steps S2011 to S2016, but when the sensed value W of the water level sensor 20 is lower than the first set-water level W1 in step S2023, the control unit 14 determines that water has not been normally supplied, stops the operation of the washing machine, including stopping water supply (S2027), and controls the display unit 22 to display a sixth error message (S2028). The sixth error message says that the water supply valve 12 is not being able to normally operate.

Further, when it is determined that the sensed value W of the water level sensor 20 is higher than the second set-water level W2 in step S2026, it means that draining has not been normally performed, so that the control unit 14 stops the operation of the washing machine, including stopping water supply (S2029), and controls the display 22 to display a seventh error message (S2030). The seventh error message says that the drain pump 10 is not being able to normally operate.

Displaying error messages through the display unit 22 in steps S2018, S2028, and S2030, respectively, was described above as the method of outputting the fifth error message, the sixth error message, or the seventh error message and this is common visual display, but unlikely, the messages may be outputted by a sounding unit such as a buzzer or a speaker.

FIG. 21 is a flowchart illustrating a method of controlling a washing machine according to a sixteenth embodiment of the present invention.

A power supply unit 19 that will be described below is a device that applies or cuts power to supply to a washing machine.

Referring to FIG. 21, when a user loads cloth and turns on the power of the washing machine 100, power is applied to the washing machine 100 from the power supply unit 19.

The user can input control commands, such as a wash course, a wash time, the number of times of rinsing, intensity of spinning, and preset register, through an input unit 15. Further, the user can make the washing machine 100 sense the laundry weight and determine an appropriate type of washing.

When the type of washing is determined, as described above, the washing machine 100 sequentially performs washing that removes the dirt on cloth, rinsing that rinses out the cloth, and spinning that spins the cloth dry (S2101, S2102, and S2103).

When the spinning is completed, the washing machine 100 can stop all of operations and standby to wait for the water remaining on the wall of the outer tub 2 or the inner tub 3 to flowing down.

The standby process may be performed only when the user specifically inputs a standby command through the input unit 15, or may be set to be always performed without input from the user.

The present embodiment is described under the assumption that a specific button for inputting a standby command is provided to the input unit 15 and the washing machine always performs the standby process if the button is pressed. For example, when the button is pressed once, the control unit 14 determines that a standby command has been inputted while the washing machine 100 is operating, and when the button is undone, the control unit 14 can determine that there is no standby command.

Therefore, the control unit 14 determines whether a standby command has been inputted through the input unit 14, when the spinning is completed. The spinning includes intermittent spinning and main spinning and the control unit 14 determines whether a standby command has been inputted, after the main spinning is finished (S2104).

When it is determined that a standby command has been inputted, the control unit 14 stops the operations of all the parts, including the water supply valve 6, the drain pump 10, and the driving unit 13 (S2105).

When water remains on the wall of the outer tub 2 or the inner tub 3, the remaining tub may freeze. Therefore, the washing machine stops all the operations and stands by until the water remaining on the wall of the outer tub 2 or the inner tub 3 completely flows down.

The standby may keep for a predetermined set-time and the control unit 14 determines whether the set-time passes during the standby (S2106). The set-time is the time for the water remaining on the wall of the outer tub 2 or the inner tub 3 to completely flows down and is determined in advance by an experiment and stored.

The water flowing down for the set-time collects in the drain channel 9 or the drain pump 10.

When the set-time has passed, it is possible to completely discharge the remaining water by driving the drain pump 10.

The water level sensor 20 senses the water level in the outer tub during the draining. The water level sensor 20 senses the water level and transmits a signal showing the water level to the control unit 14.

The control unit compares the water level sensed by the water level sensor 20 with a predetermined fully-drained water level (S2108).

When the water level sensed by the water level sensor 20 reaches the fully-drained water level, the control unit 14 stops draining after a set-time (S2109). The set-time may be set to a time for which a small amount of water can be discharged and may include zero, because a small amount of water may remain in the drain pump 10 even after the sensed water level reaches the fully-drained water level.

When draining is stopped, as described above, it is determined that the remaining water in the washing machine 100 has been completely discharged and the power is cut and turned off by controlling the power supply unit 19.

As described above, it is possible to effectively remove the remaining water in the washing machine 100 and prevent the remaining water from freezing, by ensuring a standby time for which the remaining water in the inner tub 3 and the outer tub 2 can flow down before the power is turned off, after all of washing, rinsing, and spinning is finished.

FIG. 22 is a flowchart illustrating a method of controlling a washing machine according to a seventh embodiment of the present invention.

Referring to FIG. 22, the control unit 14 performs washing, rinsing, and spinning in accordance with a wash course that is set in advance (S2201, S2202, and S2203).

When the spinning is finished, the washing machine performs cloth-unraveling for smoothly unraveling the raveled or gathered cloths (S2204).

When the cloth-unraveling is finished, the control unit 14 determines whether a standby command for removing the remaining water has been inputted from the user (S2205).

When it is determined that a standby command has been inputted, the control unit 14 stops the operations of all the parts, including the water supply valve 6, the drain pump 10, and the driving unit 13 (S2206).

The control unit 14 determines whether the set-time passes while all the parts are stopped (S2207).

When it is determined that the set-time has passed, the control unit 14 discharges all the remaining water that has flowed down, by operating the drain pump 10 (S2208).

While the remaining water is discharged, the water level sensor 20 senses the water level and the control unit 14 determines whether the sensed water level has reached a predetermined fully-drained water level (S2209).

When it is determined that the sensed water level has reached the fully-drained water level, the operation of the drain pump 10 is stopped (S2210).

When draining is stopped, as described above, the control unit 14 determines that the remaining water in the washing machine 100 has been completely discharged and cuts and turns off the power by controlling the power supply unit 19.

As described above, a washing machine that sequentially performs washing, rinsing, spinning, and cloth-unraveling can perform a standby step for removing remaining water after the cloth-unraveling. That is, it is the most effective to perform the standby step right before the power is turned off after all the operations for wash are finished.

As described above, although the embodiments of the present invention were described as being limited to performing a standby process when a standby command is inputted by a user, the present invention is not limited thereto, and the standby process may always be performed regardless of the number of times of operation of the washing machine until a user undoes the button after inputting the standby command once, and the standby process may always be performed too right before the power is turned off without specific information from the user, for a washing machine that is used under an environment with an extremely low temperature.

It should be understood that the sixteenth and seventeenth embodiments of the present invention, which were described above with reference to FIGS. 21 to 22, can be used to remove remaining water before the power of the washing machine is turned off in the other embodiments described herein. Obviously, the power of the washing machine can be turned off after any one of washing, rinsing, and spinning is completed.

FIG. 23 is a graph showing an output voltage change (a) when a water supply valve is unfrozen and an output voltage change (b) when a drain valve is unfrozen.

A washing machine according to an embodiment of the present invention can determine whether various electric components of the washing machine freeze, by sensing a change in output voltage that is outputted from the electric components, when power is supplied to the electric components.

A voltage sensing unit 18 (see FIG. 2) senses output voltages that is outputted from various electric components of a washing machine, when power is supplied to the electric components. Hereafter, the voltage sensing unit 17 may be provided to sense the output voltage of the water supply valve 6, sense the output voltage of the drain valve 8, or sense the output voltage of the drain pump 10.

In more detail, when the voltage sensing unit 17 is provided to sense the output voltage of the water supply valve 6, whether the water supply valve 6 freezes can be determined in accordance with the amount of change in output voltage of the water supply valve 6.

When the voltage sensing unit 17 is provided to sense the output voltage of the drain valve 8, whether the drain valve 8 freezes can be determined in accordance with the amount of change in output voltage of the drain valve 8.

When the voltage sensing unit 17 is provided to sense the output voltage of the drain pump 10, whether the drain pump 10 freezes can be determined in accordance with the amount of change in output voltage of the drain pump 10.

Meanwhile, the control unit 14 electrically communicates with the water supply valve 6, the drain valve 8, and the drain pump 10 and may sense whether to freeze through a change in output signal that is supplied to the control unit 14 from the water supply valve 6, the drain valve 8, and the drain pump 10.

Further, the washing machine according to an embodiment of the present invention may determine whether to freeze through the amount of change in output voltage too, which is outputted from electric components, in accordance with the circuit configuration that applies power to the electric components such as the water supply valve 6, the drain valve 8, and the drain pump 10.

Therefore, although sensing whether to freeze in accordance with the amount of change in output voltage of the water supply valve 6, the drain valve 8, or the drain pump 10 is described below, it should be understood that the present invention may sense the amount of change in output voltage of electric components such as the water supply valve 6, the drain valve 8, and the drain pump 10 and determine whether to freeze on the basis of the amount of change.

Further, the heater 28 may be disposed in the outer tub 2 to heat wash water. Alternatively, the heater 28 may be disposed in the water supply valve 6, the drain valve 8, or the drain pump 10. Further, the water supply valve 6 or the drain valve 8 may be implemented by a solenoid valve.

FIG. 23 shows an output voltage (a) of the water supply valve 6 and an output voltage (b) of the drain pump 10 that have been measured by discharging water by operating the drain pump 10 after supplying water by opening the water supply valve 6, by leaving a washing machine for a long time to freeze in a chamber set at a subzero temperature with the water supply valve 6 closed and the drain pump 10 stopping operation, and then by increasing the internal temperature of the chamber and applying a predetermined voltage to the water supply valve 6 and the drain pump 10.

As shown in FIG. 23( a), the water supply valve 6 rapidly drops in output voltage around T1 and this is because the wash water remaining in the water supply valve 6 is unfrozen around T1. That is, the water supply valve 6 unfreezes around T1. Vvalve is an output voltage value with the water supply valve 6 frozen, Vvalve_ref is an output voltage valve with the water supply valve 6 completely unfrozen, and ΔVvalve is the difference between Vvalve and Vvalve_ref.

Similarly, as shown in FIG. 23( b), the drain pump 10 rapidly drops in output voltage around T2 and this is because the wash water remaining in drain pump 10 is unfrozen around T2. That is, the drain pump 10 unfreezes around T2. Vpump is an output voltage value with the drain pump 10 frozen, Vpump_ref is an output voltage valve with the drain pump 10 completely unfrozen, and ΔVpump is the difference between Vpump and Vpump_ref.

The reason that the unfreezing time T2 of the drain pump 10 is longer than the unfreezing time T1 of the water supply valve 6 is because the amount of wash water remaining in the drain pump 10 is relatively larger than that of the water supply valve 6.

It can be seen from FIG. 23 the amounts of change ΔVvalve and ΔVpump in output voltage when the water supply valve 6 and the drain pump 10, which has frozen, unfreeze, but on the contrary, it can be expected that the amounts of change in output voltage which correspond to ΔVvalve and ΔVpump, respectively, will be sensed when the water supply valve 6 and the drain pump 10 freeze too.

Further, although a change in output voltage of the drain valve 8 is not shown in FIG. 23, the drain valve 8 may also show a similar type of change in output voltage, as shown in FIG. 23( a).

According to the present invention, the amount of change in output voltage of various electric components of the washing machine, such as the water supply valve 6, the drain valve 8, and/or the drain pump 10, is sensed, when predetermined power is applied to the electric components, and unfreezing is performed, when it is sensed that the output voltage has reduced by a predetermined value or more.

FIG. 24 is a flowchart illustrating a method of controlling a washing machine according to an eighteenth embodiment of the present invention. The method is described in more detail with reference to FIG. 24.

According to the present embodiment, whether a washing machine freezes is sensed and anti-freezing for preventing the washing machine from freezing is performed by performing unfreezing, when freezing is sensed.

The anti-freezing can be implemented in the following two ways.

First, anti-freezing automatically starts, when the washing machine is in the standby status without washing, rinsing, or spinning. It offers the advantage that it is not necessary to take a specific measure for preventing freeze of the washing machine.

Second, as shown in FIG. 2, as the anti-freezing selection unit 16 that allows selection of anti-freezing in the washing machine, anti-freezing is performed, only when there is a selection through the anti-freezing selection unit 16 by a user.

The flowchart shown in FIG. 24 can be applied in the same way to any one of the water supply valve 6, the drain valve 8, and the drain pump 10, and hereafter, the water supply valve 6 is described as an example to avoid repeat of description.

Referring to FIG. 24, the method of controlling a washing machine according to the present embodiment supplies predetermined power to the water supply valve 6 and senses an output voltage (S2401). The output voltage V of the water supply valve 6 can be sensed by a voltage sensing unit 17.

When it is sensed that the output voltage V of the water supply valve 6 has reduced by a predetermined value ΔV or more, freezing notice that says that the washing machine has frozen is displayed through the display unit 22 (S2402 and S2403). The display unit 22 may visually display the freezing notice or may aurally express it. An example of the display unit 22 in the former case may be an LCD, an LED, or a diode, and an example of the display unit 22 in the later case may be a buzzer or a speaker.

Meanwhile, when the amount of change in output voltage V is lower than the predetermined value ΔV in step S2402, the process returns to step Si and the output voltage V is sensed again.

Meanwhile, unfreezing S2404 is performed, after the freezing notice is displayed in step S2403. The unfreezing S2404 is a process of heating the water supply valve 6 by operating the heater 28 or may use the heat itself that is generated by the operation of the water supply valve 22. The heater 28 may repeat operating and suspending with a predetermined period.

The heater 28, as described above, may be provided to heat wash water (in which the heater 28 is preferably disposed in the outer tub 2), or may be disposed in the water supply valve 6 or in the drain valve 8 or the drain pump 10.

It is preferable to dispose the heater 28 in the water supply valve 6 in order to directly heat the water supply valve 6.

Meanwhile, as described above, the present embodiment can be applied to prevent the drain pump 8 or the drain pump 10 from freezing, in which it is preferable to dispose the heater 28 in the drain valve 8 in order to unfreeze the drain valve 8 and it is preferable to dispose the heater 28 in the drain pump 10 in order to unfreeze the drain pump 10.

After step S2402, the output voltage of the water supply valve 6 is sensed again (S2405), and when it is sensed that the amount of increase in output voltage V is a predetermined amount ΔV or more, the operation of the heater 28 is stopped and the freezing notice is removed (S2406 and S2407). The output voltage V of the water supply valve 6 can be sensed by a voltage sensing unit 17 in step S2405.

By contrast, when the amount of increase in output voltage V is within the predetermined value ΔV in step S2406, the process returns to step S2405 and the output voltage V is sensed again.

FIG. 25 is a block diagram illustrating the flow of control in a system for controlling freezes for a washing machine according to an embodiment of the present invention.

Referring to FIG. 25, a system for controlling freezes for a washing machine according to an embodiment of the present invention includes a washing machine 100 that can perform wire/wireless communication, a remote controller 200 that can transmit/receive signals to/from the washing machine 100 at a short distance or a long distance, and a communication medium that transmits signals between the washing machine 100 and the remote controller 200.

The washing machine can basically perform operations for washing cloth, and additionally, it can sense freezing of wash water therein and perform an operation for preventing freezing.

The washing machine 100 includes a freezing-sensing unit 110 that senses whether wash water freezes and a control unit 14 that transmits signals sensed in the freezing-sensing unit 110 to the remote controller 200.

Further, the washing machine 100 may further include an anti-freezing unit 120 that prevents wash water from freezing and the control unit 14 may control the operation of the anti-freezing unit 120 in response to an anti-freezing signal received by the washing machine from the remote controller 200.

The washing machine 100 may be equipped with any one of the freezing-sensing unit 110 and the anti-freezing unit 120 or may be equipped with both. In the following description of the present embodiment, the washing machine 100 is limited to having both of the freezing-sensing unit 110 and the anti-freezing unit 120.

The freezing-sensing unit 110 measures the internal temperature of the washing machine or checks the degree of water supplied/discharged, and transmits the information to the control unit 14, so the control unit 14 can sense freezing.

The freezing-sensing unit 110 may include a temperature sensor 18 that measures the temperature of air or the temperature of wash water in the washing machine 100 and a water level sensor 20 that senses the water level in the washing machine 100.

The washing machine 100 may include an outer tub 2 to load cloth in and the temperature sensor 18 may be disposed in the outer tub 2. When the outer tub 2 is filled with wash water at a set-water level or more and the temperature sensor 18 is submerged by the wash water, the temperature sensor 20 can sense the temperature of the wash water, and in other cases, it can sense the temperature of the air in the washing machine 100.

Further, the washing machine 100 further includes an input unit that receives various commands about the whole operation of the washing machine 100 from a user. The input unit 15 may also be configured to allow a user to directly input a request command for sensing freezing or preventing freezing.

The anti-freezing unit 120 can prevent wash water from freezing by heating the air or wash water in the washing machine, using a heater 28 or other electric components. The heater 28 may be disposed on the bottom of the outer tub 2 and heat the wash water, or may be disposed in various parts of the washing machine 100 and heat them to prevent them from freezing.

Further, the washing machine 100 may have a built-in server (not shown) that transmits/receives control information through a telephone line or the internet line.

The remote controller 200 may include a mobile phone, a computer, and a telephone. The remote controller 200 may receive and display whether wash water freezes, which is sensed by the washing machine 100, or transmits an anti-freezing signal to the washing machine 100.

The remote controller 200 may include an input unit 210 through which a request command of a user about sensing whether wash water freezes is inputted, a display unit 200 that visually or aurally expresses whether wash water freezes, and a MICOM 230 that transmits the command inputted to the input unit as a signal to a communication network 150, which is described below, or displays a signal received from the communication network 150 on the display unit 220.

The communication medium means the communication network 150 that performs data communication between the washing machine 100 and the remote controller 200. The communication network 150 may be a power line communication medium or a wireless frequency communication medium. The communication network 150 allows appropriate transmission/reception of information even though the washing machine 100 and the remote controller 200 are at a long distance, as well as a short distance.

FIG. 26 is a flowchart illustrating a first embodiment of a system for controlling freezes for a washing machine.

Referring to FIG. 26, a user may want to sense whether machine 100 in the house freezes, when being outside or traveling. In this case, the user can input a freezing-sensing command through the input unit 210 of the remote controller 200 carried (S2601).

When a freezing-sensing command is inputted to the input unit 210, the MICOM of the remote controller 200 converts the command into a signal and transmits the signal to the communication network 150. The communication network 150 transmits a freezing-sensing signal to the washing machine 100 (S2602).

The control unit 14 of the washing machine 100 can determine whether wash water in the washing machine freezes, using the freezing-sensing unit 110 (S2603). The method of sensing whether wash water freezes can be implemented in various ways.

For example, by using the temperature sensor, it is possible to determined that wash water has frozen, when temperature sensed by a temperature sensor 18 is a set-temperature or less. Alternatively, water is supplied to a set-water level through the water supply valve 6 and then the wash water is discharged by operating the drain pump 10. A change in water level is sensed by the water level sensor 20 in draining. When draining is not sufficient even though draining is performed for a set-time, it can be possible to determine that draining has not been normally performed due to freezing in the drain assembly including the drain pump 10 (S2603).

The control unit 14 determines whether to freeze in the washing machine 100, using the freezing-sensing method, and transmits a corresponding freezing determination signal to the remote controller 200, using the communication network 150 (S2604).

The MICOM 230 of the remote controller 200 can display the freezing determination signal received through the communication network 150 through the display unit 220 (S2605).

When the information about whether to freeze is displayed through the display unit 200, the user can know whether the washing machine 100 in the house has frozen, even at a long distance. When it is displayed that the washing machine has frozen, the user can rapidly take measures against the freezing, so that it is possible to reduce a breakdown of parts, including the drain assembly.

FIG. 27 is a flowchart illustrating a second embodiment of a system for controlling freezes for a washing machine.

Referring to FIG. 27, a user may want to sense whether machine in the house freezes, when being outside or traveling. In this case, the user can input a freezing-sensing command through the input unit 210 of the remote controller 200 carried (S2701).

When a freezing-sensing command is inputted to the input unit 210, the MICOM of the remote controller 200 converts the command into a signal and transmits the signal to the communication network 150. The communication network 150 transmits a freezing-sensing signal to the washing machine 100 (S2702).

The control unit 14 of the washing machine 100 can determine whether wash water in the washing machine has frozen, using the freezing-sensing unit 110 (S2703). The freezing-sensing method using the freezing-sensing unit 110 is the same as that described in the first embodiment and the description is not provided.

The control unit 14 determines whether to freeze in the washing machine 100 and transmits a corresponding freezing determination signal to the remote controller 200 through the communication network 150 (S2704).

The MICOM 230 of the remote controller 200 can display the freezing determination signal received through the communication network 150 through the display unit 220 (S2705).

When the user sees the information displayed on the display unit 220 of the remote controller 200 and wants anti-freezing to be performed, the user can input an anti-freezing signal through the input unit 210 (S2706).

When the anti-freezing signal is inputted to the input unit 210, the MICOM 230 transmits the anti-freezing signal to the washing machine 100 through the communication network 150 (S2707).

The washing machine 100 receiving the anti-freezing signal can perform anti-freezing through the anti-freezing unit 120. The operation for preventing freezing can be implemented in various ways.

For example, it is possible to prevent freezing by increasing the internal temperature of the washing machine 100, by heating wash water with the heater 28 after opening the water supply valve 6 and supplying water to a set-water level. Further, it is also possible to prevent various parts of the washing machine from freezing by operating the heaters 28 in the parts. The heater 28 may be operated until the temperature sensed by the temperature sensor reaches a set-temperature, or may be operated until a set-time has passed from the start of the operation of the heater 28.

When the anti-freezing is finished, the control unit can transmit an operation completion signal to the remote controller 200 through the communication network 150 (S2709).

The remote controller 200 can display the received operation completion signal through the display unit 220 (S2710).

The user can recognize that displayed on the display unit 220 and can go outside or travel without a concern.

FIG. 28 is a flowchart illustrating a third embodiment of a system for controlling freezes for a washing machine.

Referring to FIG. 28, when a user wants to given an instruction of an operation for anti-freezing, regardless of whether the washing machine has frozen, at a short distance or a long distance, the user can input an anti-freezing command through the input unit 210 of the remote controller 200 (S2801).

When the anti-freezing command is inputted, the MICOM 230 transmits the anti-freezing signal to the washing machine 100 through the communication network 150 (S2802).

The control unit 14 of the washing machine 100 receiving the anti-freezing signal performs anti-freezing, using the anti-freezing unit 120 (S2803).

The details of the anti-freezing are the same as those described in the second embodiment and the description is not provided.

When anti-freezing is completed, the control unit 14 transmits an operation completion signal to the remote controller 200 (S2804).

The remote controller 200 can display the received operation completion signal through the display unit 220 (S2805). 

1. A method of controlling the operation of a washing machine including at least one of a water supply pump, a drain valve, and a drain pump, the method comprising: a step (a) that senses temperature by means of a temperature sensor disposed in the water supply valve, the drain valve, or the drain pump in the washing machine; and a step (b) that operates the water supply valve, the drain valve, or the drain pump which is equipped with the temperature sensor.
 2. The method of claim 1, wherein the step (b) includes controlling the water supply valve, the drain valve, or the drain pump to repeat operating and suspending with a set-time period.
 3. The method of claim 1, wherein power is supplied to the temperature sensor through a first power supply unit, when the washing machine is in a standby status without washing, rinsing, or spinning, and power is supplied through a second power supply unit, when the water supply valve, the drain valve, or the drain pump is in operation.
 4. A method of controlling the operation of a washing machine, the method comprising: a step (a) that performs draining, when the water level in an outer tub is a set-water level or more, before supplying wash water; a step (b) that compares the internal temperature of the washing machine with a reference temperature, draining takes a reference time or more in the step (a); and a step (c) that outputs a first error message, when the internal temperature of the washing machine is lower than the reference temperature in the step (b).
 5. The method of claim 4, wherein the step (a) includes a step (a-1) that performs draining, when the water level in the outer tub is higher than a first set-water level that is set to determine whether an overflow occurs before an operation of the washing machine starts.
 6. The method of claim 5, wherein the step (b) includes a step (b-1) that compares the internal temperature of the washing machine with a first reference temperature, when the water level in the outer tub does not reach a second set-water level until a first drain-set time has passed, and the step (c) outputs the first error message, when the internal temperature of the washing machine is lower than the first reference temperature in step (b-1).
 7. The method of claim 5, wherein the step (a-1) includes outputting a second error message, when the water level in the outer tub is higher than the first set-water level; and suspending outputting of the second error message, when the water level in the outer tub reaches a second set-water level before a first drain-set time has passed.
 8. The method of claim 7, wherein the second error message is a message that says that an overflow has occurred in the outer tub.
 9. The method of claim 6, wherein the first error message is a message that says that a drain system, which discharges a washing machine in the outer tub to the outside, has frozen.
 10. A method of controlling the operation of a washing machine, the method comprising: a step (a) that performs draining, when the water level in an outer tub is higher than a first set-water level that is set to determine whether an overflow has occurred, before supplying wash water into the outer tub; a step (b) that performs draining, when the water level in the outer tub is higher than a second set-water level set to be lower than the first set-water level, after the step (a); a step (c) that compares the internal temperature of the washing machine with a predetermined reference temperature, when the time taken to discharge the water to a predetermined level in the step (b) is larger than a predetermined drain-set time; and a step (d) that outputs a first error message, when the internal temperature of the washing machine is lower than the predetermined reference temperature in the step (c).
 11. The method of claim 10, wherein the step (c) outputs a third error message, when the internal temperature of the washing machine is higher than the predetermined reference temperature.
 12. A method of controlling the operation of a washing machine, the method comprising: a step (a) that senses temperature before water is supplied into an outer tub; a step (b) that supplies water into the outer tub; a step (c) that senses the water level in the outer tub; and a step (d) that outputs a fifth error message, when the water level in the outer tub does not reach a first set-water level within a first set-time.
 13. The method of claim 12, wherein the reference temperature is set as a subzero value.
 14. The method of claim 12, wherein the step (d) includes stopping the operation of the washing machine.
 15. The method of claim 12, further comprising outputting a sixth error message, when the temperature sensed in the step (a) is higher than the reference temperature and the water level in the outer tub does not reach a first set-water level within the first set-time.
 16. The method of claim 12, further comprising a step (e) that senses laundry weight loaded in a washing tub before the step (d), wherein a target water level of the water supplied in the step (b) is set in accordance with the laundry weight sensed in the step (e), and a first set-time in the step (d) is set as a value that is longer than the time that the water level in the outer tub takes to reach the target water level, when water is normally supplied in the step (b).
 17. The method of claim 16, further comprising: a step (f) that stops supplying water and performs washing, when the water level in the outer tub reaches the target water level; a step (g) that discharges wash water in the outer tub; a step (h) that senses the water level in the outer tub during the draining; and a step (i) that outputs the fifth error message, when the water level sensed in the step (h) does not reach a second set-water level within a second set-time.
 18. The method of claim 17, further comprising outputting a seventh error message, when the water level sensed in the step (h) reaches the second set-water level within the second set-time.
 19. The method of claim 1, further comprising: a standby step that stops the operation for a set-time and stands by before power is turned off; and a drain step that removes remaining water by draining, when the set-time has passed. 